Conventionally, an actuator equipped component may actuate an actuated object equipped in an internal combustion engine such as a diesel engine. For example, Patent Document 1 discloses a supply pump as an example of the actuator equipped component. The supply pump in Patent Document 1 is equipped with an actuator, which actuates a plunger to move back and forth inside a cylinder. An actuator may have a stress concentric portion in which stress concentration may occur. It may be desirable to mitigate stress concentration in a stress concentric portion of a component of an actuator to enhance durability of the component.